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Moving Coil cartridges are plentiful and more affordable today than
ever, however designing a good phono preamp capable of amplifying the very low mc signals can be a real challenge and in fact, very
difficult if designing with vacuum tubes. We all love the sound of tubes but obtaining enough gain (60-70dB) from a minimalist two
stage preamp design is hard to accomplish without sacrificing noise and bandwidth. Add a third gain stage, or head amp, as some designers
do, and you've just introduced more noise and distortion. There's nothing worse than a humming phono pre with so much tube hiss
that it sounds like you have an ocean right in your living room!
The solution? Add a good quality step up transformer to the front
end of a medium gain phono preamp! It's not quite so difficult to design a two stage phono pre with 40-50dB of gain so the addition
of a step up transformer's 10-25dB of boost easily solves the gain issue without the addition of a noise component.
The diagram below outlines a typical application using our new 'PUP
Moving Coil kit. The step up transformers are inserted between the moving coil cartridge and a medium
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- FEATURES -
- 25dB of Gain
Enough gain to bring all moving coil cartridge outputs up to moving magnet levels.
- Nickel Laminate Construction
Nickel provides the best material for this transformer design. You can hear the difference!
- Copper and Silver Wire Coils
Our basic kit features copper
wound step up transformers or you can upgrade to the ultimate with Electra-Print's all silver wound coils.
- Ground Lift Switch
The inclusion of a ground lift switch helps
to minimize system ground loops.
- Small Compact Size
Measuring just 1.75" x 4.0" x 4.0" (44mm x 102mm x 102mm)
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'PUP is designed to minimize noise pick up. A special wiring technique is used to minimize ground induced hum. The transformer
leads are kept very short and soldered directly to the RCA connectors. And the aluminum case is grounded to increase the amount of
shielding. We also incorporate a toggle switch that allows you to connect or float the primary side ground of the transformer
thereby providing another weapon against potential ground noise. Of course we use a super high quality hermetically sealed switch
featuring all silver contacts.
Features:
The heart of 'PUP is of course the step up transformers. 'PUP uses transformers manufactured by Electra-Print
Audio renowned for winding some of the best transformers in the world! These transformers feature nickel laminates and your
choice of high purity copper or all silver coils. The 'PUP transformers provide a 1:18 step up in voltage, for a gain of 25dB, and
are well suited for moving coil cartridges requiring a load in the 30-200 ohm range.
We house the transformers in an ultra-compact enclosure. In fact it's so compact you might want to bolt it to your turntable plinth
or an equipment rack shelf. We include a set of mounting flanges (shown below) that make it easy to attach the 'PUP just about
anywhere.
It's all quite simple really, and our easy-to-follow assembly instructions will not only insure proper construction but it will have you
listening to music in no time at all.
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Medium gain moving magnet type phono preamps typically have a 47kohm
input impedance. Our step up transformer will reduce this number such that the moving coil cartridge sees an impedance of
approximately 150 ohms. Most moving coil cartridges will be quite happy with this load, however if you feel it is important to
match it exactly, a resistor can be paralleled to the output of the step up transformer thereby reflecting a nearly exact load impedance
required by your cartridge. But let us do the math for you. Just tell us the recommended load given by the manufacturer of
your cartridge along with the input impedance of your phono preamp and we'll do the rest.
'PUP is available in kit form or factory assembled by Welborne Labs
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